Indirect health effects of relative humidity in indoor environments

Journal Article · Sat Mar 01 04:00:00 EST 1986 · Environ. Health Perspect.; (United States)

DOI:https://doi.org/10.1289/ehp.8665351· OSTI ID:5200888

Arundel, A V; Sterling, E M; Biggin, J H; Sterling, T D

A review of the health effects of relative humidity in indoor environments suggests that relative humidity can affect the incidence of respiratory infections and allergies. Experimental studies on airborne-transmitted infectious bacteria and viruses have shown that the survival or infectivity of these organisms is minimized by exposure to relative humidities between 40 and 70%. Nine epidemiological studies examined the relationship between the number of respiratory infections or absenteeism and the relative humidity of the office, residence, or school. The incidence of absenteeism or respiratory infections was found to be lower among people working or living in environments with mid-range versus low or high relative humidities. The indoor size of allergenic mite and fungal populations is directly dependent upon the relative humidity. Mite populations are minimized when the relative humidity is below 50% and reach a maximum size at 80% relative humidity. Most species of fungi cannot grow unless the relative humidity exceeds 60%. Relative humidity also affects the rate of offgassing of formaldehyde from indoor building materials, the rate of formation of acids and salts from sulfur and nitrogen dioxide, and the rate of formation of ozone. The influence of relative humidity on the abundance of allergens, pathogens, and noxious chemicals suggests that indoor relative humidity levels should be considered as a factor of indoor air quality. The majority of adverse health effects caused by relative humidity would be minimized by maintaining indoor levels between 40 and 60%. This would require humidification during winter in areas with cold winter climates. Humidification should preferably use evaporative or steam humidifiers, as cool mist humidifiers can disseminate aerosols contaminated with allergens.

• Research Organization: Simon Fraser Univ., Burnaby, British Columbia
• OSTI ID: 5200888
• Journal Information: Environ. Health Perspect.; (United States), Journal Name: Environ. Health Perspect.; (United States); ISSN EVHPA
• Country of Publication: United States
• Language: English

Related Subjects

560306* -- Chemicals Metabolism & Toxicology-- Man-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AEROSOLS
AIR POLLUTION
ALDEHYDES
ANIMALS
ARACHNIDS
ARTHROPODS
CHALCOGENIDES
COLLOIDS
DISEASES
DISPERSIONS
FORMALDEHYDE
FUNGI
HAZARDS
HEALTH HAZARDS
HUMIDITY
INDOOR AIR POLLUTION
INVERTEBRATES
MITES
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
OCCUPATIONAL DISEASES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
OZONE
PLANTS
POLLUTION
SKIN DISEASES
SOLS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SYNERGISM